Many software systems such as information retrieval systems, database engines and database management systems (DBMSs) have a complex multi-layer software configuration. When developing software systems, it is often important to investigate or test the software product to discover problems or improve operation. Typically, tracing facilities are used to make simpler the process of determining problem origination or to understand the behavior of software over time. Such tracing facilities can be integrated with a software system during software testing or development and can be used for tracing the code path (i.e. which specific functions and parts of functions were called), tracing data (e.g., a network trace), tracing events and tracing the interface between two layers of software (i.e. the boundary).
For most types of software problems, it is useful to narrow down the scope of the problem. Narrowing down the scope reduces the complexity of the software system, making it easier to diagnose. Typically, in order to narrow down the problem, pieces of software or parts of a software system are removed or decoupled, at least temporarily, to eliminate components that do not cause problems.
For software products that have a multilayer structure, it may be difficult to test specific layers of code because the layers often rely heavily on each other. For example, if a software product has three layers, testing a middle layer may be difficult. The middle layer may require support from a top and/or bottom layer to execute. Because of this, it is common to use the top layer to drive the middle and lower layers. Testing the middle layer may cause unwanted and duplicate testing of the top and bottom layers, which increases the testing time for the middle layer. As large software systems normally contain many layers, testing dramatically increases this problem.
A further problem common to some cases in which software systems hang and fail to respond to any interaction arises because investigating can be a difficult task when multiple software products or components are involved. The problems that cause a hang, or other abnormal end, can be buried deep within a software system or can even be caused by circular dependencies of software system components.
Yet another problem is related to tracing of specific events within the software product. Such tracing may include errors but usually includes significant events in the software product. Even though event traces are useful, existing software systems do not provide a good overall view of behavior of all software products.
A solution to some or all of these shortcomings is therefore desired.